The Darker Heart
by Spunky0ne
Summary: When Kuchiki Soujun is killed by one of Aizen Sousuke's experimental hollows, Aizen takes a surprising action that results in the formation of an unlikely friendship with Byakuya. As the years pass and his plans play out, the bond between them is tested as Byakuya finds his thoughts about Aizen becoming more and more amorous.


**The Darker Heart**

**Theme song for the couple is "Romance" by Buck Tick...found this on YouTube and loved it instantly!**

**(I wasn't going to start any new stories for a while, but with everything that's going on in RL, I needed an outlet. And a suggestion by Baby-Ayatane for an Aizen/Bya where Aizen and Byakuya cultivate a close friendship while he is a child, then reconnect later, after Aizen's capture gave me a rare opportunity to really dig in and work out some intellectual and emotional backup. This will be a very slow burn romance that begins as a friendship and follows the characters through events spanning over a hundred years. Written in four parts, it will cover first, the time period around when Byakuya lost his father, then the time when Hisana was dying, moving on to the betrayal, then covering the time period after the Arrancar Arc and leading into the final arc. Aizen will be his wicked self, but will have an unusual connection with the Kuchiki heir, whom he finds to be intoxicatingly different from everyone else. Byakuya, too, will be reflected as in canon, but will connect strongly with Aizen before the betrayal, making him unable to hate the man when he wishes that he could. This is a dark romance and is rated 'M' for adult themes and content, but will effectively be 'T' rated through the first part and most of the second. I hope you enjoy the story!)**

**Part 1: Black Sakura**

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_**The only one who can truly understand the dark emotions of a person's soul is a heart much darker, that lives in those chilling shadows, lies unafraid in their wicked embrace and hunts that which is darker still. This is the only one who can comfort me.**_

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**Chapter 1: A Fine Hand**

"Thank you for gathering this research so quickly," Aizen Sousuke said, accepting the file of notes from the fourth division taichou with a quiet smile, "I am very curious to know if it will shed any light on the recent attacks."

"I am interested in knowing what you find as well," Unohana taichou answered somberly, "These strange hollow attacks are very distressing. Not only for the fact of taking the lives of some of our officers, but because of the rumors of some sort of strange infection in some who have lived. Aizen fukutaichou, please inform me as soon as possible of any progress that you make on this investigation."

"I will, of course," the gentle-eyed squad five fukutaichou replied.

He started to leave the room, but went still as an alert was sounded.

"Unohana taichou, please report to holding room number three. We have a high priority code seventy. The chamber has been locked down."

Aizen's eyes widened and he glanced down at the paper in his hand, then back at Unohana.

"I was afraid of this," the fourth division taichou said worriedly, "They have struck again. And this time, it is an officer."

"I see," said Aizen, a glint coming off of his glasses, "Do you think that I might accompany you?"

"Yes, I think that would be good," Unohana taichou said, starting towards the door, "But I must ask you to remain in the outer chamber and do not enter the room. We do not want to put anyone else at risk unnecessarily."

"I understand," Aizen said, falling in with her.

They moved quickly through the hallways and swiftly reached the locked chamber, where they could already hear the screeching sounds of the infected shinigami. As they came through the first entry door, Aizen found himself confronted with the shocking image of a teen youth, covered in blood and being held tightly in the grip of the squad six taichou.

"Let me go!" the boy screamed, "I have to help him! He's...!"

"You must stay back," Ginrei told the boy in a stiff voice that reflected barely managed, forced calm, "There is nothing that we can do for him. You understand? We cannot take the risk of you becoming infected. You could already be..."

"I don't care!" the youth cried, breaking away from the elder Kuchiki, "He is my _father_, and I am going to be with him! He needs me!"

"Aizen fukutaichou," Unohana said, frowning, "Would you please assist Kuchiki taichou and his subordinate?"

"Of course," Aizen agreed, turning towards the two and placing a bracing hand on Byakuya's shoulder as the teen tried to push past him.

"Get out of the way!" Byakuya shouted, his words turning into a desperate sob, "I have to go to him! He's hurt!"

"Yes," Aizen said sympathetically, "And Unohana taichou will do her best to help him. Please understand that she is only protecting you."

"He is right," agreed Ginrei, "You know that your father wouldn't want any harm to come to you. And if he was the one who caused you harm, he could never bear it."

He looked around with frustrated eyes.

"Where is that healer?" he asked in an irritated tone, "We need to make sure that Byakuya was not affected."

"I can have a look at him, if you wish," Aizen offered, "I am familiar with the case of these strange hollows and I know what signs to look for."

"I am not leaving my father until I know he is going to be all right!" Byakuya cried.

"Byakuya," Ginrei said tolerantly, "You must go with Aizen fukutaichou. Unohana taichou is with your father and will..."

He broke off as the shrieking sound of the partially hollowfied shinigami intensified and the protective barrier around the room shattered.

"Father!" screamed Byakuya, starting towards the breached chamber as Soujun surged up from the bed and turned to face his terrified son.

Byakuya froze, looking up into the eyes that had always been so gentle and kind, hypnotized by the demonic gleam that now possessed them. He felt someone's hand on his shoulder, but couldn't move to resist as Soujun gave him a fanged smile and reached out a hand to him.

"Byakuya," he said in a chilling, echoing voice, "Son, come to me."

Byakuya tore away from the hands that held him and ran towards his father, crying out his name and reaching out for him. Behind him, Aizen Sousuke looked from the infected shinigami to the teen who was surely running to meet his own death.

_This is unfortunate. Kuchiki Soujun isn't one I would have chosen to use. His soul isn't dark enough..._

While the ones around him were distracted, he reached for Kyouka Suigetsu and started the shikai release. He stopped a moment later as Byakuya reached his father and wrapped his arms around the man tightly.

"Father!" he panted, burying his face in Soujun's shoulder.

Soujun's affected eyes flickered fitfully as he glared down at the boy.

"B-byakuya..."

Aizen's eyes widened as the errant forces within the shinigami's body swelled and the reiatsu in the room rose dangerously.

"Everyone out!" Unohana taichou ordered them.

Flash steps sounded all around as the healers and Kuchiki Ginrei left the room.

"Byakuya!" Ginrei cried, looking back and realizing that the youth had not moved from within his father's arms, "Byakuya, come away from him! Hurry!"

Byakuya flinched as he felt his father's clawed fingers dig into his back. He looked desperately into Soujun's eyes for some sign of the man he remembered.

"Father!"

"Byakuya..." Soujun said, more softly.

The teen stared breathlessly as his father's eyes flickered again and began to look more normal. But even as they did, the errant forces around them grew, forcing the others back and leaving the two separate.

"I am...sorry," Soujun hissed softly, pulling a hand away to clench the place where a hole had opened up in his chest, "Byakuya, you must go now. Tell your grandfather...tell him...he will know. He will know what must be..."

"Come now, lie down," Byakuya said bracingly, "The healers can help you."

"No, _segare_, you must leave. Go with Unohana taichou and tell your grandfather to come."

"But...?"

"It will be all right," Soujun whispered, a tear leaking onto his cheek, "Everything will be fine. Please go and let the healers have a look at you. I will see you after I have seen the healers."

"W-well...if you wish, but...I will come back as soon as I have been seen."

"Good boy," Soujun whispered, kissing him on the cheek," I love you. I will be waiting for you. Go on, now."

"Yes, Father," Byakuya said, placing a kiss on his father's cheek and stepping back.

He bit at his lips and forced himself to walk back to the door, where Ginrei stood, wearing an unreadable expression.

"Aizen fukutaichou, will you please take Byakuya to an examination room?"

"Of course. Come Byakuya-kun. I will see to your injuries."

"I wasn't hurt," Byakuya said numbly, "The blood is all his...except for..."

His voice faded and he walked silently alongside Aizen, his eyes on the floor and his reiatsu carefully drawn inward.

"I am sorry that this happened to you," Aizen said, surprising himself with his own sincerity, "But I understand that you conducted yourself well, under the circumstances."

"Thank you," the young noble said absently.

They had almost reached the examination room when a howl rose up from down the hallway and Soujun's reiatsu swelled dangerously, then exploded and began to fade. Byakuya turned, a horrified look on his face as he flash stepped back down the hall and ran into the room, just in time to see Soujun's possessed body shatter and fade away. Ginrei stood in the chamber, his weapon drawn in one shaking hand and his expression devastated as he met his grandson's eyes.

G-grandfather," Byakuya said shakenly, his face going deadly white, "Grandfather, what did you do?"

Guilt erupted over Ginrei's normally calm face and he stood still, unable to answer. Aizen looked from elder Kuchiki to younger, an odd, choking feeling falling over him as tears ran down Byakuya's bloodstained face.

_Unacceptable._

_This is too much suffering for those meant to live. But, the boy will be infected now. And while it would certainly yield useful information, for some reason I can't fathom, I don't want this to happen._

He placed his hand on Kyouka Suigetsu and breathed the invoking words. Healers and nobles fell quickly into the thrall of his zanpakutou and he swiftly rewrote what had happened in the room. He lifted the hypnotized boy into his arms and carried him into another examination room, where he cleaned away the blood and healed him to the best of his ability.

_This cannot stop the hollowfication, but a seal will control it until such time as I might make use of it. Yes, an insurance policy that he will be available for me to use, if needed..._

He placed the seal carefully, then laid a blanket over the boy and nodded in approval.

"This will not be an easy thing for you. But you and your uncle will be spared memory of that event for now. It would not do to have the noble families overly motivated to track down the perpetrators of the hollow anomalies right now. No, this will slow down the pursuit and give me more time to conduct my studies."

He told himself that was all there was to his seemingly merciful action.

"Rest now. When you wake, you will only remember being injured and brought here for healing. All of that other unpleasantness will be forgotten as well. The accepted story everyone will believe is that Soujun was killed by a strong Arrancar and that you valiantly defended him and evacuated him from the scene. It is better that way. We can deal with the rest of this at another time."

He left the lad sleeping and returned to the others, then spent some time rewriting their memories, fixing the details cautiously to avoid arousing suspicion. When his work was concluded, he led Ginrei to his grandson's room and sat him down at Byakuya's side. He made himself unseen and caused Unohana taichou to enter the room. The healer leaned over the teen and examined him for a moment, then nodded, smiling kindly.

"There should be no lasting effects," she told a relieved looking Ginrei, "He will recover fully."

"That is good to know," Ginrei said, his voice holding a deep sadness.

"Can you tell me what happened?" Unohana asked softly.

"They were conducting a search for clues around the area of one of the strange attacks and were surprised by a powerful Arrancar. Soujun was protecting Byakuya, when he was injured attacking the hollow. Byakuya defended him and killed the hollow, but even though he was able to bring Soujun back, my son was fatally injured. He only managed a short goodbye to Byakuya and me before he succumbed to his injuries."

"I am so very sorry, Kuchiki taichou," Unohana said sincerely, "I will see that word is sent to your clan and that Soutaichou is notified."

"Thank you," Ginrei said quietly.

He gazed down sorrowfully at Byakuya's troubled sleeping face.

"He has endured too much for one so young," he commented, "With his mother lost bearing him and his grandmother passing so recently. I am tired of seeing sadness in that boy's eyes. He bears the pain well. He makes me so proud, but I wish that it wasn't so difficult for him."

"He is young and very resilient," said the healer, "He will mourn his father, of course. But he will come through it. Perhaps I can suggest a counselor for him to see for a time."

Aizen's eyes widened and he made a small adjustment to the illusion controlling them.

"I understand that Aizen Sousuke has some experience in this area. And he and Byakuya share an interest in calligraphy, so they would have a common ground. Would you like me to ask him to spend some time with your grandson?"

Ginrei considered the words, looking down at Byakuya and taking a slender, pale hand into his.

"I would ask that it be kept completely confidential. We don't usually go outside of clan healers for such things, given our rules for strict privacy. But we could let it be known that Aizen fukutaichou is instructing him in calligraphy. That should allay unnecessary attention."

"Very well," said Unohana taichou, "I will speak to Aizen fukutaichou and be in contact with you soon."

"Thank you, Unohana-san," Ginrei said gratefully, "I appreciate your help. Things are going to be difficult with funeral arrangements and such. With so much going on, I think my grandson will need a diversion."

"Then, it is settled. I will let you know when I have word on where the sessions will take place."

Ginrei nodded silently, then returned to looking down at Byakuya as the healer left them alone. Byakuya's chest rose and fell steadily, his breaths slow and even as he slept.

"I am sorry," Ginrei said softly, "Sorry that you had to witness the violence that took him, and that you alone bore the burden of protecting and returning him. Thank you for slaying the foul beast that took him from us. I am in your debt, my grandson. Rest quietly now and regain your strength. You will need it for the times that lie ahead. With Soujun lost, you become the hope of our clan. It will be a difficult honor to bear. But you are very strong, Byakuya. You will be all right."

He went quiet then, holding Byakuya's hand and looking out the window, watching as the sky darkened and the rain began to fall.

Aizen slipped out of the room and walked slowly back through the rain to the fifth division. As he walked, he found himself haunted by the events he had altered.

_Yes, now the burden of that memory falls on me. But my heart is darker than yours, Byakuya-kun, and will bear it more easily. Be glad that this is how it is. I don't think that a young, pure heart like yours could bear the truth._

_Don't worry, I'll never expect your gratitude for me making those changes. As much as they eased your mind, they served my purposes too. This is the way of the world...but it is interesting how our needs have collided and brought us into each others' realms. I wonder what will happen._

_Yes...I am truly curious where this will go._


End file.
